Condensed Consolidated Statements of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Common Stock [Member]	Additional Paid-in Capital [Member]	Total Accumulated Other Comprehensive (Loss) Earnings [Member]	Foreign Currency Translation Adjustments [Member]	Unrealized Derivative Gains (Losses) [Member]	Minimum Retirement Benefit Liability Adjustments [Member]	Deferred Compensation [Member]	Retained Earnings [Member]	Treasury Stock at Cost [Member]	Treasury Stock Held for Deferred Compensaton [Member]	Total
Balances at Sep. 30, 2018	$ 106	$ 185,705	$ (74,942)	$ (39,794)	$ (20,942)	$ (14,206)	$ 8,431	$ 1,966,643	$ (539,408)	$ (8,431)	$ 1,538,104
Balance, Common Stock, shares at Sep. 30, 2018	72,960
Balance, Treasury Stock, shares at Sep. 30, 2018									(11,203)
Balance, Treasury stock held for deferred compensation, shares at Sep. 30, 2018										(202)
Net earnings								126,699			126,699
Other comprehensive earnings (loss), net of tax			10,173	266	9,275	632					10,173
Cash dividends paid								(18,914)			(18,914)
Purchases of treasury stock									$ (43,253)		(43,253)
Purchases of treasury stock, shares									(457)
Sales of treasury stock		(3,152)							$ 27,302		24,150
Sales of treasury stock, shares									745
Common shares issued from treasury stock for benefit plans		9,173							$ 5,673		14,846
Common shares issued from treasury stock for benefit plans, shares									158
Stock-based compensation		13,166									13,166
Purchases and transfers of stock by/to deferred compensation plan							625			$ (625)
Purchases and transfer of stock by/to deferred compensation plan, shares										(8)
Distribution of stock from deferred compensation plan							(180)			$ 180
Distribution of stock from deferred compensation plan, shares										4
Balances at Mar. 31, 2019	$ 106	204,892	(64,814)	(39,573)	(11,667)	(13,574)	8,876	2,112,168	$ (549,686)	$ (8,876)	1,702,666
Balance, Common Stock, shares at Mar. 31, 2019	72,960
Balance, Treasury Stock, shares at Mar. 31, 2019									(10,757)
Balance, Treasury stock held for deferred compensation, shares at Mar. 31, 2019										(206)
Balances at Dec. 31, 2018	$ 106	195,894	(64,651)	(40,541)	(10,413)	(13,697)	9,015	2,044,695	$ (535,362)	$ (9,015)	1,640,682
Balance, Common Stock, shares at Dec. 31, 2018	72,960
Balance, Treasury Stock, shares at Dec. 31, 2018									(11,096)
Balance, Treasury stock held for deferred compensation, shares at Dec. 31, 2018										(209)
Net earnings								77,579			77,579
Other comprehensive earnings (loss), net of tax			(163)	968	(1,254)	123					(163)
Cash dividends paid								(10,106)			(10,106)
Purchases of treasury stock									$ (43,253)		(43,253)
Purchases of treasury stock, shares									(457)
Sales of treasury stock		(2,489)							$ 23,256		20,767
Sales of treasury stock, shares									638
Common shares issued from treasury stock for benefit plans		9,173							$ 5,673		$ 14,846
Common shares issued from treasury stock for benefit plans, shares									158		158
Stock-based compensation		2,314									$ 2,314
Purchases and transfers of stock by/to deferred compensation plan							34			$ (34)
Distribution of stock from deferred compensation plan							(173)			$ 173
Distribution of stock from deferred compensation plan, shares										3
Balances at Mar. 31, 2019	$ 106	204,892	(64,814)	(39,573)	(11,667)	(13,574)	8,876	2,112,168	$ (549,686)	$ (8,876)	1,702,666
Balance, Common Stock, shares at Mar. 31, 2019	72,960
Balance, Treasury Stock, shares at Mar. 31, 2019									(10,757)
Balance, Treasury stock held for deferred compensation, shares at Mar. 31, 2019										(206)
Cumulative effect from adoption | ASC 606 [Member]			(45)	(45)				38,745			38,700
Cumulative effect from adoption | ASU 2016-16 [Member]								(1,005)			(1,005)
Balances at Sep. 30, 2019	$ 106	207,120	(103,306)	(53,235)	(4,955)	(45,116)	9,382	2,224,919	$ (602,098)	$ (9,382)	$ 1,726,741
Balance, Common Stock, shares at Sep. 30, 2019	72,960										72,960
Balance, Treasury Stock, shares at Sep. 30, 2019									(11,040)		(11,040)
Balance, Treasury stock held for deferred compensation, shares at Sep. 30, 2019										(211)	(211)
Net earnings								144,691			$ 144,691
Other comprehensive earnings (loss), net of tax			35,930	(2,807)	37,626	1,111					35,930
Cash dividends paid								(27,525)			(27,525)
Purchases of treasury stock									$ (13,346)		(13,346)
Purchases of treasury stock, shares									(124)
Sales of treasury stock		(2,521)							$ 15,246		12,725
Sales of treasury stock, shares									363
Common shares issued from treasury stock for benefit plans		9,420							$ 5,328		14,748
Common shares issued from treasury stock for benefit plans, shares									124
Stock-based compensation		13,475									13,475
Purchases and transfers of stock by/to deferred compensation plan							624			$ (624)
Purchases and transfer of stock by/to deferred compensation plan, shares										(6)
Distribution of stock from deferred compensation plan							(43)			$ 43
Distribution of stock from deferred compensation plan, shares										1
Balances at Mar. 31, 2020	$ 106	227,494	(67,376)	(56,042)	32,671	(44,005)	9,963	2,342,340	$ (594,870)	$ (9,963)	$ 1,907,694
Balance, Common Stock, shares at Mar. 31, 2020	72,960										72,960
Balance, Treasury Stock, shares at Mar. 31, 2020									(10,677)		(10,677)
Balance, Treasury stock held for deferred compensation, shares at Mar. 31, 2020										(216)	(216)
Balances at Dec. 31, 2019	$ 106	216,158	(93,548)	(43,467)	(4,575)	(45,506)	9,911	2,268,483	$ (592,596)	$ (9,911)	$ 1,798,603
Balance, Common Stock, shares at Dec. 31, 2019	72,960
Balance, Treasury Stock, shares at Dec. 31, 2019									(10,814)
Balance, Treasury stock held for deferred compensation, shares at Dec. 31, 2019										(215)
Net earnings								91,318			91,318
Other comprehensive earnings (loss), net of tax			26,172	(12,575)	37,246	1,501					26,172
Cash dividends paid								(17,461)			(17,461)
Purchases of treasury stock									$ (13,346)		(13,346)
Purchases of treasury stock, shares									(124)
Sales of treasury stock		(577)							$ 5,744		5,167
Sales of treasury stock, shares									137
Common shares issued from treasury stock for benefit plans		9,420							$ 5,328		$ 14,748
Common shares issued from treasury stock for benefit plans, shares									124		124
Stock-based compensation		2,493									$ 2,493
Purchases and transfers of stock by/to deferred compensation plan							81			$ (81)
Purchases and transfer of stock by/to deferred compensation plan, shares										(1)
Distribution of stock from deferred compensation plan							(29)			$ 29
Balances at Mar. 31, 2020	$ 106	$ 227,494	$ (67,376)	$ (56,042)	$ 32,671	$ (44,005)	$ 9,963	2,342,340	$ (594,870)	$ (9,963)	$ 1,907,694
Balance, Common Stock, shares at Mar. 31, 2020	72,960										72,960
Balance, Treasury Stock, shares at Mar. 31, 2020									(10,677)		(10,677)
Balance, Treasury stock held for deferred compensation, shares at Mar. 31, 2020										(216)	(216)
Cumulative effect from adoption | ASC 842 [Member]								$ 255			$ 255